Question: Expand.
Answer: $\begin{aligned} ( x{-4})(x+7)&= x(x+7){-4}(x+7) \end{aligned}$ $\begin{aligned} \phantom{( x{-4})(x+7)}&=x^2+7x-4x-28 \\\\ &=x^2+3x-28 \end{aligned}$